The Post Sports Live crew dissect the Redskins performance in the loss to the Eagles on Monday night. (Post Sports Live/The Washington Post)

The players in green jogged past, smiles on their faces, greeted by name and with a handshake by Philadelphia Eagles owner Jeffrey Lurie.

Running backs ran by, linebackers zipped past, linemen came and went until only one was left. The door stayed open until Michael Vick, the Eagles’ quarterback, jogged through the hallway, a football tucked in his arm, the evening’s final carry — and a convincing effort and an attention-grabbing victory now behind him.

“One down,” Vick said as he entered the locker room.

One game into the new Eagles’ first season, one win against the division foe Washington Redskins. Philadelphia ran 77 offensive plays, and if not for first-year Coach Chip Kelly’s decision to slow things down in the fourth quarter, it could’ve been far more.

This was America’s first look at an offense expected to change the NFL, this up-tempo attack that, as per its design, left the Redskins and their fans unable to catch their breath Monday night. If it’s a gimmick offense, it’s at least an effective gimmick — for one game, anyway.

This is an offense that, if this keeps up, is going to cause headaches for the NFC East all season and perhaps beyond. It has all the makings of the league’s latest offensive flavor, and as Redskins defensive coordinator Jim Haslett learned Monday night, all the makings of defenses’ nightmare.

“The one thing we learned,” Kelly said after the 33-27 win, “is there’s a lot of things we can do better.”

Kelly brought this offense with him from the University of Oregon, where he tried each Saturday to push the limits of how long his offense can hold onto the ball. More snaps presumably mean more chances to score, and at least in the first half Monday, the only thing that seemed to slow the Eagles was the Eagles. Vick had a first-quarter pass batted down and ruled a fumble, which DeAngelo Hall returned for Washington’s first touchdown. Later, Vick missed open receivers and overthrew others, reviving questions that the 33-year-old quarterback was maybe unable to run an offense that relies so heavily on proficiency.

Then the old man settled in, and the Redskins gasped. The crowd hushed. The scoreboard lit up and then lit up again. A few Washington players crumpled to the FedEx Field turf, in much better condition than it was the last time the Redskins played here, and grabbed ankles and calves.

Were they faking injuries? Was this the only way to catch their breath? DeSean Jackson, the Eagles’ best wide receiver, thought so.

“A couple guys were going down with cramps and things like that to kind of slow us down,” said Jackson, who nonetheless had 104 receiving yards. “Not sure how serious the injuries were and things like that, but as far as the offense, we’re like, ‘Come on, let us keep going.’ ”

In the first half, the Eagles ran a staggering 53 offensive plays, more than twice the number of Washington’s snaps and not far from the average number of snaps that NFL teams attempted in 2012.

Kelly admitted after his first NFL victory that, yes, he eased off the gas in the second half, even as the Redskins tried to return fire. They had 70 offensive plays for the game, though that was more out of desperation than design.

Regardless, Kelly said he was still adjusting to the NFL game and its differences from Pacific-12 football. Though after one week, maybe it’s the NFL and, in particular the Redskins, New York Giants and Dallas Cowboys that need to adjust to Kelly.

“Everybody was kind of caught off guard on our team as far as the Redskins saying they were used to playing versus a high-tempo offense,” Jackson said. “Buffalo did it, but us coming out, being able to show high-intensity and go up and down so easily was a great opportunity for us.”

Washington will spend the next few days wondering how Monday night went wrong; how, with months to think about and prepare for Philadelphia’s offense, it still looked overmatched. Meanwhile, the Eagles will try to keep sharpening a weapon that now has the league’s attention — and has brought validation to Kelly’s offense.

This didn’t seem like Steve Spurrier trying to bring a college power to the big leagues, or Nick Saban attempting his detail-oriented approach with the Miami Dolphins. This seemed more like Kelly offering something more complicated than NFL coaches are used to — but something they’ll have to figure out quickly.

One down, as Vick said, and 15 more to go. Monday was just one game; however the Eagles and their opponents deal with the future will determine how legitimate Kelly and Philadelphia can be in the long run.

In the short-term, though, Jackson pointed out something that now seems obvious.

“A lot of teams,” he said, “better get in shape.”